Previously, the jacks for telephone, computer and data network were directly mounted on a cover plate for the jack or on a patch panel. FIGS. 1(a), 1(b) and 1(c) show a jack 10 having two barbed pieces 12 and 15 (wherein the piece 12 is elastic) having on their tips an inclined surface 13 which engages the window 14 of the cover plate 11, where the jack 10 is inserted from the rear of the cover plate 11 and projects beyond the window 14 by sliding the inclined surface 13 therethrough to respectively stop the barbed pieces 12 and 15 on the window 14 so as to fix the jack in place as shown in FIG. 1(a), and the sectional assemblage is shown in FIG. 1(b). Such a structure has the following drawbacks:
1) The jack 10 will protrude over the cover plate surface especially when the plug 17 is secured into the jack 10, which causes much inconvenience in use and an untidy appearance as shown in FIG. 1(b). PA0 2) The jack 10 and the through hole 14 of the cover plate 11 have therebetween a clearance 16 which prevents the jack 10 and the cover plate 11 from tightly engaging with each other and from keeping out dust or the other foreign matter as shown in FIG. 1(c).
Similarly, mounting a jack on a network patch panel will also exhibit the above-mentioned problems.
On the other hand, FIG. 2(a) shows a modified jack 23 to be secured on a square wall 22 by projecting into the window 21 of the cover plate 20, where the square wall 22 and the cover plate 20 are integrally formed. Further, corresponding to the respective barbed pieces 24 and 25 of the jack 23, the square wall 22 includes two traverse media 26 and 27 for securing the respective barbed pieces 24 and 25 so as to retain the jack 23 in position. Accordingly, this modification prevents the jack 23 from protruding over the cover plate surface and avoids the clearance therebetween, as shown in FIG. 2(b). But, such a structure cannot be applied on a patch panel because the patch panel is a metallic product which cannot be made with a wall around its window when pressed. Besides, this modified jack does not provide a color for identification and does not have a display hole containing therein a display plate for showing a functional attribute of the jack, which further limits its practical and commercial value.
Arnett (U.S. Pat. No. 5,238,426) discloses an adapter mounted on a panel plate to hold a jack. The adapter includes two parallel side portions and two moveable arms. To fix the adapter on the opening of the panel plate, each of the arms further includes two detents, and each of the parallel side portions further includes a depending portion. Furthermore, to engage the jack, the adapter further includes two grooves provided on the inner walls of the parallel side portions respectively for receiving therein the barbs of the jack. To remove the adapter from the panel plate, the user must apply force to the free end portions of the arms. Therefore, the free end portions of the arms must extrude from the front surface of the panel plate. The other problem of Arnett's device is that, it cannot be applied to the jack with barbs as shown in FIGS. 1(a) and 2(a), which is a popularly used type of jack.